McGee has a 4.98 ERA over 21 2/3 innings this season, converting 15 of 18 save opportunities. He blew a save Friday night against the Padres, allowing four runs in the ninth inning, including Wil Myers' go-ahead three-run home run.

McGee has a 4.98 ERA over 21 2/3 innings this season, converting 15 of 18 save opportunities. He blew a save Friday night against the Padres, allowing four runs in the ninth inning, including Wil Myers' go-ahead three-run home run.

"We've got to check out McGee," Rockies manager Walt Weiss said. "The last pitch he threw last night, he may have hurt his knee. He's getting an MRI this morning, and we'll go from there when we get the results."

Weiss said he will use Carlos Estevez as the primary closer and Jason Motte when the rookie is unavailable. Estevez has a 4.43 ERA over 20 1/3 innings in his rookie season and was a closer last season in the Minors, and Motte has a 2.84 ERA over 6 1/3 innings after starting the season on the 15-day DL with a right shoulder strain and was a closer with the Cardinals and Cubs.

"[Motte's] at the point, where I've been planning on using him to protect leads in the seventh and Estevez in the eighth," Weiss said. "I've had Motte for the most part when he's available penciled in to protect the seventh. I look at him as a back-end guy right now."

Anderson has a 2.35 ERA over 30 2/3 innings across three levels this season, including a 2.12 ERA over three starts for Triple-A Albuquerque. He will start Sunday's game against the Padres, making his Major League debut.